Centerless grinding and polishing machine



Jan. 2, 1951 K. w. MACDONALD CENTERLESS GRINDING AND POLISHING MACHINE Filed Nov. 15, 1949 6 Sheets-Sheet l I l/J Jan. 2, 1951 Filed Nov. 15, 1949 K. W. MACDONALD CENTERLESS GRINDING AND POLISHING MACHINE 6 Sheets-Sheet 2 Jan. 2, 1951 K. w. MACDONALD CENTERLESS GRINDING AND POLISHING MACHINE 6 Sheets-Sheet 3 Filed Nov. 15, 1949 Jan. 2, 1951 I K. w. MACDONALD 2,536,757

CENTERLESS GRINDING AND POLISHING MACHINE Filed Nov. 15, 1949 s Sheets-Sheet 4 Jan. 2, 1951 K. w. MACDONALD CENTERLESS GRINDING AND POLISHING MACHINE 6 Shee ts-Sheet 5 Filed NOV. 15, 1949 K. w. MACDONALD CENTERLESS GRINDING AND POLISHING MACHINE Jan. 2, 1951 6 Sheets-Sheet 6 Filed Nov. 15, 1949 1&9. .10.

IE! L Patented Jan. 2, 1951 CENTERLESS GRINDING Ann POLISHING MACHINE Kenneth W. Macdonald, Arlington, Masa, assignor to Production Machine Company, Greenfield, Mass, a corporation of Massachusetts Application November 15, 1949, Serial No. 127,343

1 r This invention relates to centerless grinding and polishing machines, and the object is to improve and perfect machines of the type shown in prior patent to Rufus W. Fuller No. 1,421,205.

This well known type of centerless grinding and polishing machine operates upon cylindrical rods, tubes, pipes or the like, and comprises a grinding or polishing wheel or belt, together [with a feeding wheel or belt, which feeding device cooperates with a worksupport to hold the work being operated upon in proper position and to simultaneously and automatically rotate and feed the same lengthwise during the grinding, polishing, or finishing operation. Such .machines necessarily require adjustments to take care of varying diameters of material being operated upon, as well also as adjustments for determining the feeding of the work through the .machine for efficient and effective operation.

a My present invention is directed to improve such adjustable mechanisms as are necessary and to facilitate the movement of the grinding or polishing wheel or belt to fit the diameter of the work and also to compensate for wear, such adjustment being readily effected during the continuous operation of the machine. Also, the feeding devices, whether a wheel or a belt, require adjustment towardv and from the cooperating grinding or polishing instrumentalities A to afford the desired pressure on the work, as well as the speed of feedingthe work through the machine. V

Further important features of the present invention consist in the mounting and arrangement of the feed elements, with means for angular adjustment of the feeding devices to predetermine the speed of travel of the work through the machine, also while in continuous operation, and means to maintain the feeding belt, where a belt is used for the feed, in desired tension during the adjustments. as well as means.

of a larger diameter, and-being automatically and proportionately raised when the adjustment is" for a smaller diameter of work to be operated upon, eliminatingprior loose linkage connections heretofore used. KI:

'4 Claims. (01. 51 103) Other'importantimprovements and novelties consist in the construction and arrangement" of 1 the machine whereby a motorto actuate the grinding or polishing is mounted in fixed relation on a slide so that both the motor and the entire grinding or polishing and operative con:

nections are-movable toward and from the work for spacing and adjusting, as well as to com-' pensate. for wear, thus greatly simplifying the connecting and operating means.

Similarly, a separate motor is mounted and arranged on the movable slide carrying the feeding devices as the same are adjusted toward or from the work. This arrangement greatly simplifies the connections and constructions where adjustments necessary are involved, and enables me to also provide a relatively simple and efficient motor for the feed, such as or H. P.,

and a similarly efficient motor for the grinding and polishing, such as-5 to 7 H. P.

A still further important and novel feature consists in the mounting of feeding instru-j mentalities which allow for both the adjust ments toward and from the work and with a variation in speed, as well as adjusting the angular position'of feed, with capacity also for yielding toward and from the work, the feeding devices being'held in uniform tension irrespective of the point to which the same are adjusted. My novel constructionfor varying the speed of travel of the feeding and work-engaging elements during the continuous operation of the machine and in full view of the operator results in a finer grade of work and maximum eificiency of both the operator and machine. For this purpose, I mount the feeding devices on a set of parallel links supporting the samein proper alignment with the grinding or polishing elements, and provide a variable speed pulley which is readily adjustable for varying speeds with the driving belt cooperating thereby, while' maintaining the belt'under proper tension.

My novel arrangement of the parallel link supporting elements further allows automatically.

for handling tapered work, permitting the feeding devices to yield during the increasing taper of work as it isfed through the machine without Further details, combinations, and novel i1 provements and advantages willbe hereinafter more fully pointed out and claimed.

Referring to the drawings illustrating a preferred embodiment:

Fig. 1 is a plan view of my improved centerless grinding machine construction;

Fig. 2 is a side elevational view of the front or operative side of the machine;

Fig. 3 is an enlarged longitudinal cross-sectional view of the line 33 of Fig. 1;

Fig. 4 is a cross-sectional view on the line 4--4 of Fig. 8;

Fig. 5 is a cross-sectional view on the line 55 of Fig. 3;

Fig. 6 is a cross-sectional view on the line 6-6 of Fig. 7;

Fig. 7 is a cross-sectional view'on the line 1-"! of Fig. 2;

Fig. 8 is an end view of the feed belt looking from the left of Fig. 3;

Fig. 9 is a fragmentary view partly in crosssection looking from the left of Fig. 8;

Fig. 10 is a view on the line l0=-l0 'of Fi 3; and

Fig. 11 is a perspective view on a reduced scale of the supporting frame.

Referring to the drawings, I designates .generally a rectangular supporting base or frame having legs 22 and a top plate 3, which top 18 provided with slideways 4 and 5 (see Fig. 11). These slideways are arranged substantially opposite each other in the lengthwiseportion of the top plate 3, a slide 6 being arranged to traverse the slideway 4, which slide carries the grinding wheel 1 mounted on an upstanding support 8 on said slide 6 and also the motor 9 which rotates the grinding wheel 7. Similarly the feeding-devices are mounted on a slide l0 adapted to traverse the slideway 5, which slidecarries both the feeding devices andthe operating motor therefor, whereby the feeding instrumentalities and their motor and the grinding wheel and its motor are adjustably movable toward and from the work designated at 15, see Figs. 2 and 3,:as will be explained.

While I have herein illustrated the grinding wheel land its attached motor, it will be appreciated that the slide 5 may be removed and a duplicate slide fitted therein which would carry a belt-grinding or polishing device and operating motor therefor, thesame being interchangeable with the wheel I and its motor 9 as herein illustrated. 7

The wheel 1 is secured at one end of a shaft ll mounted in suitable bearings I8-l'8 in the upstanding support 8 and is held imposition by discs l9l9 secured by a threaded nut 29 on the reduced end portion 2| of the shaft 1 I. The o'pposite end of the shaft "carries a pulley '22, pref erably a multiple belt pulley as indicated in Fig. 1, with the belts 23-23 driven by a pulley 24 on an armature 25 of the motor 3, which motor is also mounted on the slide 6 by means of a separate sliding support 28, to which the motor 9 is attached by a pair of bands 29--29 and is adjustably secured to the slide 5. In order to tighten the belts 23, a shouldered lug 3 0 and adjusting screw 3| are provided, which latter is threaded through a block 32 attached to the slide 6. exhaust chamber 35 is connected to a dust hood 36*exte'nding over the wheel I in order to remove the material ground or polished from the work during the operation of the machine, as indicated in Figs. 2 and 3.

In order to afford an adjustment of the slide 5 carrying the wheels 1' and motor '9 toward and from the work 5,-I aflixto the slid'e' a depending 'in'e'sn or to disconnect the bevelled gears 44 by a slight longitudinalmovement. Thus, the slide 5 can be moved into desired adjusted position to accommodate the machine to the varying diameters of the wheel I or to compensate for wear on the wheel I.

The devices for feeding the work in cooperation with the grinding and polishing wheel 1' are carried by a slide 15 in the slideway 5 and comprise an upper and lower frame, connected by parallel links, carrying the power drive and feedactuating devices all pivotally supported by the slide 10.

Referring to Fig. 2, the motor 12 is carried'by supports depending from the upper frame '60 through an opening 50 in the top plate '3, see Fig. 1-1, said motor being held-by a band iii to which a bracket 52 is'secured, said-bracket in turn being attached to an upper bracket 53 secured to a pair of vertically extending adjusting supports 56-43% which supports extend vertically through an arcuate slot I l in the slide 10 'and an opening in the plate 3 to the upper frame 6t, and are raised and lowered by rotatinga wheel .55 having a handle 55 mounted in the upper frame 'fiiL and thereby varying the speedof feed by controlling the effective diameter of the variable speed pulley 13 and travel of the belt 12, to be explained.

This frame 60 is pivota'lly connected to pairs of links 5l5| and 62-62 on each side of the frame 50 by pivots S3-153 and 34 64, respectively; and at the lower "opposite ends 'saidlinks are pivotally connected to the bottom frame 65,

as indicated at and '61, see Fig. 2, all pivots being ball-bearing 'as indicated at 59, Fig. 5. Guideways l2l2 "on the plate 3 hold the slide H] assembled thereon, and the slide Ill carries the upper and lower frames and connecting elements.

The frame 60 may thus be moved toward and from the work I5 while maintained in horizontal position, said frame 60 carrying the work-feeding devices, the vertical adjusting supports 54, and motor 12. A

Mounted in suitable bearings in the frame 60 is a shaft 1i! 'having aton'e end a pulley Tl connected by a belt 12, with the variable speed pulley i3 'moun'tedon the armature shaft-of the motor 12. The belt 12 "can'be tightened or loosened and the "puue'y 13 expanded of contracted, to be later explained. Onthe opposite end of'the shaft ll] is "a worm gear T4 meshing with a-c'oira sponding gear 15 mounted on a shaft :16 'car r'ied in suitable bearings in a part [94, to be described, at one end of the frame 60, which shaft has a sprocketwhe'elll connected by a sproeket'ch'ain T8 to a shaft 19, haviiig a'eorresponuing sprocket wheel 83 and apulley'fl'l. Said pulley carries the feeding belt 82 "passing over an idler '33, verticany depending, :seerig. '3, said idler 83 being secured on'a shaft'84, both' shafts l9 and'84 being mounted insu'itable bearings on an extension 85 secured to the frame 60.

Thus, power. from the motor..l2 rotates the belt 82., .and the entire work-feeding mechanism can bemoved toward or from the work, swinging on horizontal and vertical pivots, andfixedin the positions where so moved and maintained in substantially uniform yielding contact with .ithe work, as will be. described.

g The adjusting supports to carry the motor I2 and to act on pulley I3 and belt 82comprisepairs of threaded members, the lower supports '54 be ing provided with the threaded sockets in which the threaded stems 85 of the connecting members extend, which members .pass through .tubular bearings 81 formed on the top frame 60, see Fig.

4; 1 One member carriesthe operating wheel -55 together with a sprocket wheel 88, and theother member has a sprocket wheel 89 connectedby-a sprocket chain 90. Thus, rotation of thewheel 55 simultaneously raises and lowers the motor- I2 to expander contract the pulley I3. a

r The lower frame 65 is attached to the slide I by a pivot 9| extending through a boss 92 (see Fig. 3) and fitted into a corresponding socket-93 formed on the slide I0. Thus, theentire feeding instrumentalities canbe swung horizontally-on the'pivot 9I, thereby adjusting the horizontal line of contact of the feed belt 82 on the work and can be bodily moved toward and from th work I on the slide I0. 'A set screw 94 extends through a-curved slot 95' in the frame 65 and is threaded into a tapped recess 96' in the slide I0- (see Figs. 3 and which screw 94 can be tightened to lock the frame 65 in the angular position relative with the slide I0, to which the feeding mechanism may be set for the horizontal angle desired of the feed belt 82 to meet the taper of the work I5, as required. a

A rack bar 91 secured to the under part of the slide I0 (see Figs. 3 and 10) is engaged by the teeth of a quarter gear 91, which is keyed inthe shaft 46 and turned by the wheel 58 to move the slide l0 and its supported mechanism towardand from the work. The shaft 46 slides'lengthwise to engage and disengage the mitre gears 44 and 45 to effect adjustment of the wheel] and attached motor and operating connections, as already described. Thus a single hand wheel 48, in convenient .position at the operators side of the machine, is used to adjust both grinding or' polishing wheel and the feeding belt toward and from the work. 1

It is desirable to move the feeding belt 82 away from the wheel 1 without disturbing the adjustments to which the slide I0 and operating devices have been effected in order to place or release the work. For this purpose, I arrange to move the top frame 60 on the parallel links by means of a handle I00 formed with a split base clamped by a threaded screw IOI on a shaft I02 mounted in a bracket I04 on the slide 3 (see Fig. 3) with the opposite end of the shaft keyed to a lever I05 positioned to contact a'plug I06 to engage and move the parallel links to the left, viewing Figs. 2 and 3, against the tension of a coiled spring I08. This spring has one end hooked to an extension of the bracket I04 and the other to a bar .IIO bolted to the top frame 60, the spring therewhich the plug I06 will strike when the handle This construction insures a relatively slow and,

steady motion to the movement of the top frame as the piston constitutes an air cushionboth' against the swinging of the handle I00 and the. return action of the spring I08.

In order to tighten the feeding belt 82, I mount the shaft 84 carrying the lower pulley 83 on one end of a bell crank arm I (see Figs. 3, 6, and 9) the shaft 84 extending through a housing I26 projecting through an opening I2I in the side of the extension 85. The other arm I28 of the bellorank arm is mounted in an extensionI30-rearwardly of the part 85, as shown in Fig. 3, and is wardly extending lug I34 is controlled by thrust-. ing and tightening screws as indicated at I38,. Fig. 2. Thus the belt 82 may be loosened for re-i placement or tightened, and at all times is yieldingly impelled toward the work.

I also prefer to mount the pulleys and 83 on ball-bearing raceways as indicated in Fig. 7 at I31. Preferably, also, the outer peripheries of each belt-carrying pulley 80 and 83 are flanged as indicated at I40.

I find it desirable to supply a positive backing element to support the feeding belt 82 directly opposite to the line of contact with the work I5 between the pulleys 80 and 83. For this purpose, see Fig. 3, I provide a slide MI in the extension midway between the pulleys B0 and 83, in which slide a headed plunger I44 is fitted with its head I45 holding a metal plate I46 in direct support-' ing contact with the inner surface of the belt 82, and with a rearward extension formed as a rack bar I48 in mesh with a pinion I49 on a shaft I50. Rotation of the shaft I50 adjusts the pressure of the plate I46 against the belt. Belt guides I5I are'carried by the plate M6.

In addition to the horizontal angle obtained by swinging the feeding belt and its operating connections on the pivot 8|, which is to fit the machine for operating on tapered work, it is also.

For this purpose, the entire extension 85 is supported on the upper frame 50 so as to be capable of being partially rotated about a pivot in alignment with the shaft 10 and with effective -opera-' tive position of the wheel I and belt 82 on the work I5. 7

I design the as shown in Fig. 4 at I80, which encloses a hollow cylindrical casting I8I adapted to turn in bearings I82-I82 in the opposite end portions of the frame 50, which casting, in turn, carries ball bearings at I83-I83 for the shaft 10 in concentric assembly. A set of gear teeth I85 are formed in the upper quarter of the casting I8I in position to meshwith a worm I85 on a shaft I88 set in bearings in a boss I89 which is a part ofthe frametli and crosswise therein. Thereby. rotav' upper frame 50 of cylindrical form" tion of the shaft I88 rotates "the casting l8l and, hence, the vertical angle of the belt on the work.

The locking engagement of worml Stand teeth I85 serve to hold these parts in adjusted position, but it is desirable to provide a positive lock which will be described. The squared end I89 of the shaft 188 projects to enablea wrench to be applied thereto through an opening I90 inthe cover 20!, to turn the shaft and effect the adjustment desired. A scale or gauge I91, may be convenient-,

1y provided to indicate the relative rotation to which these parts are adjusted. The extension frame 85 maybe'attached to the supporting casting ill! in any suitable manner. As here shown, I preferably form the end of the casting 8! with ahead I94, see 'Figs. 2 and 3, which enclose the worm .14 on .theend of the shaft ill and the gear 15, the open end of thishead I94 having a peripheralrlange bolted to the extension 85. To lock these parts in adjusted position, I supply a bolt 1 95 passing through a slot H6 in a part I55 of the frame 69 and threaded into the head I9 1 at I98, see Figs. 3 and 5.

To automatically raise and lower a work support [10 as the slide it is moved toward or from the wheel '4 to provide space for stock of varying diameter, I fit the lower end of the work sup-port in a holder H! by threaded connections, see Fig. 3. This holder has-a hub 72 frictionally tight on a stud I13 at the upper-end of a sliding rod I14 held in an angularly positioned holder H5 afiixed to the plate 3. The lower end of the slidin'g rod I74 has a hub H6 through which a headed bolt l'l'l extends into a cam slot at I99 formed at a predetermined angle with the holder H5, as part of a bracket 202, secured to the under part of theslide'lfl, see Fig. 5.

A roll I19 on the bolt lil is also fitted to tray erse the cam slot as the slide it! is moved and, hence, to pull down or push up the rod i7 5 and, hence, the work support to adjust the same for varying diameters of work and to hold the work in the proper and efficient line of contact between the wheel I and feeding belt 82, as is customary in centerless grinding and polishing machines of this type. A cover 2M is removably fitted to protect the machine against dust, abradings, etc. and the operator also.

While a wheel 7 and belt 82 are herein shown and described, an abrading belt in place of the wheel 7 can be substituted and for this purpose I form the base i with a recess 29% to receive the lower idler for such a belt substitution. Also the feed belt 82 can be interchanged with a wheel by removal of the extension frame 85 and replacing with wheel bearing and driving connections.

The operation will now be described. As adjustment of the motor 9 and wheel is onl occasionally required, but, if desired, the operator pushes on the wheel 5.8 until the gears and 45 are in mesh, and then turns the wheel 26 moving the slide 6 in the slideway i on the plate 3 as needed. Thereupon the wheel -48 and shaft are retracted until the gears 5d and t5 are in mesh, and. the feeding mechanism including the belt 82 and its motor i2 are moved by adjusting the slide it in its slideway in the plate 3 to properly space the belt 82 and polishing, grinding,

apparatusismoved toward orfrom the wheel 1,

thru the action of the roll He traversing the; slot I95, secured rigidly to the slide :0 and, hence, insuring a positive and accurate positioning of the wolk support.

Thereupon, the vertical angle of the belt 82 is adjusted by loosening tne locking bolt B and turning the shalt we to a point indicated on the scale la: and the locking screw lilo is then tightened. This angular ad ustment of the extension 85 and belt 82 provides the desired speed or travel of the work past the wheel 7.

The operator then moves the lever lfiil, viewing- FigsfZ and 3, swinging the top frame 68 and connections against the tension of the spring 108 to open the working space between the reed belt 82 and wheel 1 and, thereupon, positions the work and releases the lever luu, and the frame 50 vis forced slowly back, because of the oasnpot effect of the piston llt', thereby yie.d1ngly holding the belt 82 in contact with the work in cooperation with the spring on the idler s3.

Motors 9 and I2 are then energized and the polishing, grinding, and feeding of the work proceecls. lf tapered Work is being operated upon. theframe Bu moves proportionately on the par allel linAS supporting it, as the taper ofthe Work increases, while the belt s2 is maintained in vertical position and alignment without any loosening of the driving and belt-tightening actions. The wheel 55 is rotated to control the speed of travel of the feeding belt by expanding or contracting the variable speed pulley '|3-such as-a Reeves pulley-while keeping the driving .belt 12 tight. Covers 2M and 2113 ad 121 protecting themechanism. Thus, the main base and slides,

frames, and motors can be standardized and'kept in stock .to be fitted with belt or wheel-polishing or feeding apparatus, as ordered.

I claim:

-1. A centerless grinding and polishing machine of the kind described, comprising a working element, work-feeding elements, a work support, .a slide adjustably movable toward and from the working element, a frame pivotally attached to said slide, a second frame supported on the firstmentlonecl frame by parallel links, said second frame carrying the work-engaging feeding elements, and connectionsbetween the second frame and work-engaging elements providing for angu-..

lar adjustment relatively with the work.

2. in a centerless grinding and polishing machine of the kind described, a slide carrying the.

Workng elements and an operating motor therefor, a second slide carrying work-feeding elements and an operating motor connected therewith, independently adjustable means to movethe working element and motor and the-work'- feedlng elements and its motor toward and from each other, in combination with means including para lel links and means tensioning the feeding element toward the work, together with individually adjustable devices to predetermine the horizontal and vertical angle of the feeding elements on the work.

3. In a centerless grinding and polishing ma chine .of the kind described, aworking element.

a work support adjacent said element, .work-..

feeding instrumentalities adapted to hold and feed the work on said support and in contact with the working element, comprising a, slide adjustable toward and from the work, a frame pivotally attached to said slide and angularly adjustable thereon, a, second frame supported by parallel links on the first frame, yielding means to move the second frame toward the work, said second frame carrying a work-engaging and feeding belt adjustable about a horizontal angle, said belt including a driving pulley and an idler, the idler being mounted on a bell crank lever, and independently adjustable and yielding tensioning means acting on the idler to hold the belt tensioned against the work.

4. A centerless grinding and polishing machine of the kind described, comprising a working element, a work-feeding element, a movable work support between said two elements, a motor to drive said feeding element, a slide carrying said feeding element and motor, means to adjust the slide toward and from the working element, a bracket rigidly secured to said slide, a, slot in said bracket angularly positioned relatively with 10 the direction of travel of the slide, in combination with connections from said angular slot to the work support to move said work support in 00- operative relation with the travel of the workfeeding slide.

KENNETH W. MACDONALD.

REFERENCES CITED The following references are of record in the 

